This publication project will: 1) Gather information about the nonbibliographic, machine-readable data files containing national health care data pertaining to periods later than January 1, 1970 that have been created by public and private sector organizations throughout the United States and that are available to researchers outside the sponsoring organizations. This information will be gathered from published materials, from telephone conversations and correspondence with the sponsors of health-related machine-readable data files, and from file documentation obtained from the sponsors. 2) Write standardized abstracts of each of these files (estimated to be between 200 and 250) in accordance with the recommendations given in Sue Dodd, Cataloging Machine-Readable Data Files: An Interpretive Manual (Chicago: American Library Association, 1982). Each abstract will include a standardized bibliographic citation of the file, as well as bibliographic citations of the documentation of the file and of publications related to the file; it will also include information about the methodology employed in the collection of the data and about the file's geographic and time coverage, purpose and scope, subject coverage (expressed as Medical Subject Headings (MeSH), technical characteristics, and availability. 3) Publish the abstracts in a form suitable for ready reference by interested health care researchers as a special issue of either Journal of Medical Systems or Review of Public Data Use. The abstracts will be arranged and indexed so that they can be searched for by data file sponsor, by data file title, and by Medical Subject Headings.